During the years 1848-1850, Denmark was embroiled in the First War for Schleswig-Holstein (also known as the Three-Year War), a prolonged civil war in Denmark's southern territories, which later became a focus for German nationalism. Finally finding his place in the monarchy, Frederik played his part as king very well during the war. His dignified yet populist behaviour endeared him to the people, and cemented the union of monarchy and democracy that was to characterise the Danish system ever since. This is not to say that Frederik immediately understood the limitations which constitutional monarchy imposed upon him - far from it. Among other gaffes, his resistance to a partitioning of Schleswig (during the war) caused politicalhavoc.

King Frederik devoted considerable effort to making his Louise acceptable to the upper circles of Danish society - efforts which were ultimately in vain. The nobility and the elevated bourgeoisie were not about to accept a social climber into their midst, even if she were the consort of the King. As a result, Frederik and his not-Queen spent much time in the countryside - and, contrary to the capital, the people in the countryside loved their King and his ladylove.